I just purchased bunch of Quads and I am wanting to run Ubuntu 14.04 on them (because of "reasons"). I have hard time getting the ethernet working on these units.

"ETH0 could not attach PHY" errors and such.

Ethernet works on 16.04 but I cant currently use as I specifically require these units to run 14.04. Is there any way of getting the ethernet working with older 14.04?Both Ubuntu images were downloaded from Wandboards site.

The issue is that the newer (rev D1 boards) require an updated device tree so that the Ethernet PHY gets powered up. Older Wandboards did not require that because they have no PMIC.Running the older kernel should be OK, but, you will have to update the device tree that is used on boot.

So can I just take the "imx6q-wandboard-revd1.dtb" file from the 16.04 boot image and drop it to the older systems boot image?I assume some config file "somewhere" needs to be modified to tell the system to use the new dtb file?

Googling and searching this forum does not exactly provide any simple guide for this. Any pointers?

I think that can only work if the kernel versions were exactly the same between Ubuntu 14 and 16, which is not the case. Device trees are compiled against the specific kernel that they will be used with.However, I have done that successfully with Yocto when the kernel was the same version.U-boot uses the device tree that is named in this file:

/boot/extlinux/extlinux.conf

We have a similar situation with Yocto, in that only the latest versions (Rocko and Pyro) can be used on rev D1 boards, if you want the Ethernet port to work.